From WO-A-93/18532 a photoelectrochemical cell is known which consists of two thin conductive glass layers adjoined each by transparent thicker isolating layers. The core of the cell is formed by a porous titanium dioxide layer acting as an electrode. Between the porous titanium dioxide layer and the thin conductive glass layers a thin diffusion layer of non-porous titanium dioxide is arranged. The principle of this arrangement of a photovoltaic cell, which has become known among experts also under the name of Graetzel cell, can be gathered from EP-B-0 525 070 in which mainly the composition of the suitable dyes is dealt with.
In spite of attempts by various parties to commercialize a Graetzel type cell, up to now production of a photochemical cell of the type mentioned above with sufficient size has not been
There are further patent documents (e.g. DE-A-34 41 044 and EP-A-0 528 212) referring to the application of the conductive layers, in particular metal or metal oxide layers, onto thin conductive glass panes. In addition, for manufacturing of dye solar cells of the type mentioned above the application of technologies is known from EP-A-0 739 020 and EP-A-0 582 212 which permit step by step forming of the desired layer stack in successive print processes. Between the successive printing steps thermal curing of each layer may be required. The desired result of a homogeneous stack of layers requires, as is made clear by the known technologies, strict observance of the processing parameters specified, such as e.g. substrate concentration, temperature, and duration of reactions. Especially in step by step forming of dye cells the various used materials should be matched concerning their coefficients of expansion. achieved or successfully achieved thus far. Also the efficiency of these cells still is very unsatisfactory, which is another reason why commercial success thus far has not been achieved. Furthermore, manufacturing costs of the known modules are still too high, which prevents economical application on a large scale.
It thus is the objective of the present invention to propose a phtovoltaic cell and a method of its manufacture, which achieves high economic feasability and best reliability.
This objective is met by a photovoltaic cell presented by the features according to patent claim 1 and by a method of manufacture presented by the features according to patent claim 10.
The inventive photovoltaic cell presents the important advantage that using a relatively simple structure particularly effective sealing of the cell is achieved. It has proven particularly advantageous if butyl rubber or similar materials are used as sealing materials. In the manufacturing method it has proven particularly suitable if utmost care is taken in cleaning the glass panes in a plurality of cleaning steps in order to achieve optimum adherence of the conductive layers on the glass substrate and to avoid formation of larger bubbles during the coating of the glass cover.